title: Fast ion surface energy loss and straggling in the surface wake fields.
abstract: We have measured the stopping powers and straggling of fast, highly ionized atoms passing through thin bilayer targets made up of metals and insulators. We were surprised to find that the energy losses as well as the straggling depend on the ordering of the target and have small but significantly different values on bilayer reversal. We ascribe this newly found difference in energy loss to the surface energy loss field effect due to the differing surface wake fields as the beam exits the target in the two cases. This finding is validated with experiments using several different projectiles, velocities, and bilayer targets. Both partners of the diatomic molecular ions also display similar results. A comparison of the energy loss results with those of previous theoretical predictions for the surface wake potential for fast ions in solids supports the existence of a self-wake.
authors.affiliation: Inter-University Accelerator Centre, JNU New Campus, New Delhi 110067, India. nanditapan@gmail.com
authors.forename: T
authors.initials: T
authors.lastname: Nandi
authors.forename: K
authors.initials: K
authors.lastname: Haris
authors.lastname: Hala
authors.forename: Gurjeet
authors.initials: G
authors.lastname: Singh
authors.forename: Pankaj
authors.initials: P
authors.lastname: Kumar
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kumar
authors.forename: S K
authors.initials: SK
authors.lastname: Saini
authors.forename: S A
authors.initials: SA
authors.lastname: Khan
authors.forename: Akhil
authors.initials: A
authors.lastname: Jhingan
authors.forename: P
authors.initials: P
authors.lastname: Verma
authors.forename: A
authors.initials: A
authors.lastname: Tauheed
authors.forename: D
authors.initials: D
authors.lastname: Mehta
authors.forename: H G
authors.initials: HG
authors.lastname: Berry